1. Field of the Invention
The invention relates to a control device for the presser mechanism of a sewing machine, with an operating lever activatable in the same direction for lifting and for lowering the presser mechanism. The operating lever is operatively connected to the presser bar via a double level. The double lever is, in turn, operatively connected to a releasable locking mechanism by way of an index member guided in an inherently closed, controlled cam route with associated detent catch.
2. Description of Background Art
In a control device of the type disclosed, for example, in U.S. Pat. No. 4,333,407, dated June 8, 1982, a cam route is fashioned with a detent catch positively engaged by an index member after release of an operating lever when the operating lever is actuated for the first time. Thus, the lifted presser bar remains locked in a lifted position. Only with a renewed actuation of the previously released operating lever is it possible for the index member to leave the detent catch, whereupon the presser bar is again lowered into its operative position, suitably under the effect of a spring.
However, in many instances, it is desirable to place the presser mechanism into its lifted position for a more or less short period of time without locking it into such position. This is impossible by means of the aforementioned device. The engagement of the index member into the detent catch upon release of the first-actuated operating lever necessitates a relatively large rearward movement of the operating lever and a correspondingly large backward stroke of the index member and the presser mechanism. Thus, the presser mechanism is locked in place considerably below its maximum possible lifting height. Therefore, manipulating thick sewing material with the presser mechanism in the locked condition is thus possible only with difficulty.